An image sensor device includes a pixel array for detecting light and recording intensity of the detected light. For example, the pixel array responds to the light by accumulating a charge. The higher the intensity of the light is, the higher the charge is accumulated in the pixel array. The accumulated charge is used to provide image information for use in a suitable application, such as a digital camera. Some image sensor devices use phase difference detection pixels to perform autofocus (AF). Phase difference detection works by disposing focus detection pixels among image sensing pixels. The signals output from the focus detection pixels are used to detect phase differences between signals generated by different focus detection pixels. The detected phase differences can be used to perform AF.